The subway train offers access to all twelve intersections downtown. If every intersection is .75 miles apart and the train travels at 20 mph and spends 45 seconds at every stop to unload and onboard new customers, how long will it take to get from the first intersection to the last intersection?
When you do a question like this use a similar smaller question to see what is happening.
I have given you my solution to an alternate question.
I decided to look at the same question but with only 4 stop. I draw the train line on a piece of paper.
The distance travelled was 0.75*3 = 2.25miles
1hour/20miles * 2.25miles = 0.1125hours = 0.1125*60min = 6.75minutes = 6 minutes and 45 seconds
The number of stops where the train waited was only 2 because the first and last don't count.
stops = 2*45seconds = 90seconds = 1 minute and 30 seconds
6 minutes and 45 seconds + 1 minute and 30 seconds = 8minutes and 15 seconds.
This answer is for 4 stops only.
Try copying the method only do it for the whole 12 stops.
When I did it i got 32minutes and 15seconds but I haven't checked my working so if you get a different answer it doesn't necessarily mean that you are wrong.
Good luck. If you do some but get stuck you can ask for help again.